Preparing small crystal ssz-32 and its use in a hydrocarbon conversion process

ABSTRACT

The invention is directed to a method of making a small crystal SSZ-32 zeolite, known as SSZ-32X. The catalyst is suitable for use in a process whereby a feed including straight chain and slightly branched paraffins having 10 or more carbon atoms is dewaxed to produce an isomenized product, with increased yield of isomerized material and decreased production of light ends.

FIELD OF THE INVENTION

This invention is directed to a method of making a catalyst comprising asmall crystal intermediate pore size zeolite, specifically SSZ-32. Thecatalyst is suitable for use in isomerizing a feed which includesstraight chain and slightly branched paraffins having 10 or more carbonatoms.

BACKGROUND OF THE INVENTION

The production of Group II and Group III base oils employinghydroprocessing has become increasing popular in recent years. Catalyststhat demonstrate improved isomerization selectivity and conversion arecontinually sought. As discussed in U.S. Pat. No. 5,282,958, col. 1-2,the use of intermediate pore. molecular sieves such as ZSM-22, ZSM-23,Z:SM-35, SSZ-32, SAPO-11 SAPO-31 SM-3,SM-6 if) isomerization andshape-selective dewaxing is well-known. Other typical zeolites useful indewaxing include ZSM-48, ZSM-57 SSZ-20, EU-I, EU-13, Ferrierite, SUZ-4,theta-1, NU-10, NU-23, NU-87, ISI-1, ISI-4, KZ-1, and KZ-2.

U.S Pat. No. 5,252,527 and 5,053,373 disclose a zeolite such as SSZ-32which is prepared using an N-lower alkyl-N′-isopropyl-imidazolium cationas a template. U.S. Pat. No. 5,053,373 discloses a silica to aluminaratio of greater than 20 to less than 40 and a constraint index, aftercalcination and in the hydrogen form of 13 or greater. The zeolite ofU.S. Pat. No. 5,252,527 is not restricted to a constraint index of 13 orgreater. U.S. Pat. No. 5,252,527 discloses loading zeolites with metalsin order to provide a hydrogenation dehydrogenation function. Typicalreplacing cations can include hydrogen ammonium, metal cations, e.g.,rare earth, Group IIA and Group VIII metals, as well as their mixtures.A method for preparation of MTT-type zeolites such as SSZ-32 or ZSM-23using small neutral amines is disclosed in U.S. Pat. No. 5,707,601.

U.S. Pat. No. 5,397,454 discloses hydroconversion processes employing azeolite such as SSZ-32 which has a small crystallite size and aconstraint index of 13 or greater, after calcinations and in thehydrogen form. The catalyst possesses a silica to alumina ratio ofgreater than 20 and less than 40 U.S. Pat. No. 5,300,210 is alsodirected to hydrocarbon conversion processes employing SSZ-32. TheSSZ-32 of U.S. Pat. No. 5,300,210 is not limited to a small crystalsize.

SUMMARY OF THE INVENTION

The instant invention is directed to a small crystal SSZ-32zeolite(hereinafter referred to as SSZ-32X) which is suitable fordewaxing a hydrocarbon feed to produce an isomerized product. It is alsodirected to a method of making this zeolite, and to dewaxing processesemploying catalyst comprising SSZ-32X. The feed to the process includesstraight chain and slightly branched paraffins having 10 or more carbonatoms. The feed is contacted under isomerizaticon conditions in thepresence of hydrogen with a catalyst comprising an SSZ-32X. Thiscatalyst possesses, in comparison with standard SSZ-32, less definedcrystallinity, altered Argon adsorption ratios, increased externalsurface area and reduced cracking activity over other intermediated poresize molecular sieves used for isomerization. Use of this catalyst inisomerization results in a higher lube product yield and lower gasproduction.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1(a), 1(b) and 1(c) illustrate comparisons between the x-raydiffraction patterns of standard SSZ-32 and SSZ-32X.

FIG. 2(a) and 2(b) illustrate a comparison of yield and VIcharacteristics for use of SSZ-32X in Isodewaxing, compared with that ofstandard SSZ-32.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Catalyst Preparation

Novel SSZ-32 zeolites can be suitably prepared from an aqueous solutioncontaining sources of an alkali metal oxide or hydroxide, an alkylamine(such as isobutylamine) an N-lower alkyl-N′-isopropyl-imidazolium cation(preferably N,N′-diisopropyl-imidazolium cation orN-methyl-N′-isopropyl-imidazolium cation) which is subsequentlyion-exchanged to the hydroxide form, an oxide of aluminum(preferablywherein the aluminium oxide source provides aluminum oxide which iscovalently dispersed on silica), and an additional oxide of silicon. Thereaction mixture should have a composition in terms of mole ratiosfalling within the following ranges: TABLE 1 Composition of mole ratiosBroad Preferred SiO₂/Al₂O₃ 20-less than 40 30-35 OH—/SiO₂ 0.10-1.00.20-0.40 Q/SiO₂ 0.05-0.50 0.10-0.25 M+/SiO₂ 0.05-0.30 0.15-0.30H₂O/SiO₂ 20-300 25-60 Q/Q+M+ 0.25-0.75 0.33-0.67wherein Q is the sum of Q_(a) and Q_(b).

Q_(a) is an N-lower alkyl-N′-isopropyl-imidazolium cation (preferably anN, N′-diisopropyl-imidazolium cation orN-methyl-N′-isopropyl-imidazolium cation). Q_(b) is an amine.Isobutyl,neopentyl or monoethyl amine are suitable examples of Q_(b)although other amines may be used. The molar concentration of amine,Q_(b) must be greater than the molar concentration of the imidazoliumcompound, Q_(a). Generally the molar concentration of Q_(b) is in therange from 2 to about nine times the molar concentration of Q_(a). U.S.Pat No. 5,785,947 (herein incorporated by reference) describes how azeolite synthesist method employing two organic sources, one sourcebeing an amine containing from one to eight carbons provides significantcost savings over a method in which the quaternary ammonium ion source(:such as imidazolium) is the only source of organic component. Thecombination of the 2 organic nitrogen sources allows the possibility ofthe primary template (used in smaller quantity) to nucleate the desiredzeolite structure and then the amine to contribute to filling the poresin a stabilizing manner, during crystal growth. Empty pores of highsilica zeolites are susceptible to re-dissolution under the synthesisconditions. The amine also can contribute to maintaining an elevatedalkalinity for the synthesis.

M is an alkali metal ion, preferably sodium or potassium. The organiccation compound which acts as a source of the quaternary ammonium tonemployed can provide hydroxide ion.

The cation component Q_(a), of the crystallization mixture is preferablyderived from a compound of the formula

wherein R is lower alkyl containing 1 to 5 carbon atoms and preferably—CH3 or isopropyl and an anion (AΘ) which is not detrimental to theformation of the zeolite. Representative of the anions include halogens,e.g., fluoride, chloride, bromide and iodide, hydroxides, acetate,sulfate, carboxylate, etc. Hydroxide is the most preferred anion.

The reaction mixture is prepared using standard zeolitic preparationtechniques. Typical sources of aluminum oxide for the reaction mixtureinclude aluminates, alumina, and aluminum compounds, such asaluminum-coated silica colloids (preferably Nalco 1056 colloid solalthough other brands may be used) Al₂ (SO4,)₃, and other zeolites,

In a preferred method of preparing zeolite SSZ 32SX, we have found thatproviding sources of aluminum oxide to a zeolite synthesis mixturewherein the aluminum oxide is in a covalently dispersed form on silicaallows zeolites with increased aluminum content to be crystallized.Increased alumina content promotes isomerization. In another approachzeolites of pentasil structure and lower silica/alumina ratios(approximately 10) can be used as aluminum oxide sources or feedstocksfor the synthesis of zeolite SSZ-32X. These zeiolites are recrystallizedto the new SSZ-32X zeolite in the presence of the organic sources Q_(a)and Q_(b) described above.

Mordenite and ferrierite zeolites constitute two such useful sources ofaluminum oxide or feedstocks. These latter zeolites have also been usedin the crystallization of ZSM-5 and ZSM-11 (U.S. Pat. No. 4,503,024).

In another preferred approach, wherein the aluminum oxide is in acovalently dispersed form on silica is to use an alumina coated silicasol such as that manufactured by Nalco Chem. Co. under the product name1056 colloid sol(26% silica, 4% alumina). In addition to providing novelSSZ-32 X with high aluminum content, use of the sol generatescrystallites of less than 1000A (alorg the principal axis) withsurprisingly high isomerization capability.

Indeed, the catalytic performance of SSZ-32X (in the hydrogen form) forcracking capability is manifested by Constraint index values (as definedin J. Catalysis 67, page 218) of 13 or greater and preferably from 13 to22. Determination of Constraint index is also disclosed in U.S. Pat. No.4,481,177. In general, lowering the crystallite :size of a zeolite leadsto decreased shape selectivity. This has been demonstrated for ZSM-5reactions involving aromatics as shown in J. Catailysis 99,327 (1986).In addition, a zeolite ZSM-22, (U.S. Pat. No. 4,481,177) has been foundto be closely related to ZSM-23 (J. Chem. Soc. Chem. Comm. 1985 page1117). In the above reference on ZSM-22 it was shown that ball-millingthe crystallites produced a catalyst with a constraint index of 2.6.This is a surprisingly low value for this material given other studieswhich indicate that it is a very selective 10-ring penitasil (Proc. of7th Intl. Zeolite Conf. Tokyo, 1986, page 23). Presumably theballmilling leads to a less selective but more active catalyst, byvirtue of producing smaller crystallites. So it is surprising here, thatsmaller crystallites maintain high selectivity in the case of SSZ-32X.

Typical sources of silicon oxide include silicates, silica hydrogel,silicic acid, colloidal silica, fumed silicas, tetraalkyl orthoslicates,and silica hydroxides, Salts, particularly alkali metal halides such assodium chloride, can be added to or formed in the reaction mixture. Theyare disclosed in the literature as aiding the crystallization ofzeolites while preventing silica occlusion in the lattice.

The reaction mixture is maintained at an elevated temperature until thecrystals of the zeolite are formed. The temperatures during thehydrothermal crystallization step are typically maintained from about140° C. to about 200° C., preferably from about 160° C. to about 180° C.and most preferably from about 170. degree. C. to about 180° C. Thecrystallization period is typically greater than 1 day and preferablyfrom about 4 days to about 10 days.

The hydrothermal crystallization is conducted under pressure and isusually in an autoclave so that the reaction mixture is subject toautogenoius pressure. The reaction mixture can be stirred whilecomponents are added as well as during crystallization.

Once the zeolite crystals have formed, the solid product is separatedfrom the reaction mixture by standard mechanical separation techniquessuch as filtration or centrifugation. The crystals are water-washed andthen dried, e g., at 90° C. to 150° C. for from 8 to 24 hours, to obtainthe as-synthesized zeolite crystals. The drying step can be performed atatmospheric or subatmospheric pressures.

During the hydrothermal crystallization step, the crystals can beallowed to nucleate spontaneously from the reaction mixture. Thereaction mixture can also be seeded with SSZ-32 crystals both to direct,and accelerate the crystallization, as well as to minimize the formationof undesired aluminosilicate contaminants.

SSZ-32X can be used as-synthesized or can be thermally treated(calcined). Usually, it is desirable to remove the alkali metal cationby ion exchange and replace it with hydrogen, ammonium, or any desiredmetal ion. The zeolite can be leached with chelating agents, e.g., EDTAor dilute acid solutions, to increase the silica alumina mole ratio.SSZ-32X can also be steamed. Steaming helps stabilize the crystallinelattice to attack from acids.

SSZ-32X can be used in intimate combination with hydrogenatingcomponents for those applications in which ahydrogenatlion-dehydrogehnation function is desired. Typical replacingcomponents can include hydrogen, ammonium, metal cations, e.g. rareearth, Group IIA and Group VII metals, as well as their mixtures.Preferred hydrogenation components include tungsten, vanadium,molybdenum, rhenium, nickel, cobalt, chromium, manganese, platinum,palladium (or other noble metals).

Metals added to affect the overall functioning of the catalyst(including enhancement of isormerization and reduction of crackingactivity) include magnesium, lanthanum (and other rare earth metals),barium, sodium, praseodymium, strontium, potassium and neodymium. Othermetals that might also be employed to modify catalyst activity includezinc, cadmium, titanium, aluminum, tin, and iron.

Hydrogen, ammonium as well as metal components can be exchanged intoSSZ-32X. The zeolite can also be impregnated with the metals, or, themetals can be physically intimately admixed with SSZ-32X using standardmethods known to the art. And, the metals can be occluded in the crystallattice by having the desired metals present as ions in the reactionmixture from which the SSZ-32 zeolite is prepared.

Typical ion exchange techniques involve contacting the SSZ-32X with asolution containing a salt of the desired replacing cation or cations.Although a wide variety of salts can be employed, chlorides and otherhalides, nitrates, and sulfates are particularly preferred.Representative ion exchange techniques are disclosed in a wide varietyof patents including U.S. Pat. Nos. 3,140,249; 3,140,251; and 3,140,253.Ion exchange can take place either before or after SSZ-32X is calcined.

Following contact with the salt, solution of the desired replacingcation, SSZ-32X is typically washed with water and dried at temperaturesranging from 65° C., to about 315° C. After washing SSZ-32X can becalcined in air or inert gas at temperatures ranging from about 200° C.to 820° 0 C. for periods of time ranging from 1 to 48 hours or more, toproduce a catalytically active product especially useful in hydrocarbonconversion processes.

The SSZ-32X zeolite described above is converted to its acidic form andthen is mixed with a refractory inorganic oxide carrier precursor and anaqueous solution to form a mixture. The aqueous solution is preferablyacidic. The solution acts as a peptizing agent. The carrier (also knownas a matrix or binder) may be chosen for being resistant to thetemperatures and other conditions employed in organic conversionprocesses. Such matrix materials include active and inactive materialsand synthetic or naturally occurring zeolites as well as inorganicmaterial such as clays, silica and metal oxides. The latter may occurnaturally or may be in the form of gelatinous precipitates, sols, orgels, including mixtures of silica and metal oxides. Use of an activematerial in conjunction with the synthetic SSZ-32X ie., combined withit, tends to improve the conversion and selectivity of the catalyst incertain organic conversion processes.

SSZ-32X is commonly composited with porous matrix materials and mixturesof matrix materials such as silica, alumina, titania, niagrnesia,silica-alumina, silica-magnesia, silica-zirconia, silica-thoria,silica-berylla, silica-titania, titania-zirconia as well as ternarycompositions such as silica-alumina-thoria, silica-alumina-zirconia,silica-alumina-magnesia and silica-magnesia-zirconia. The matrix can bein the form of a cogel. In the instant invention, the preferred matrixmaterials are alumina and silica. It is possible to add metals for theenhancement of catalytic performance, during the actual synthesis ofSSZ-32X, as well as during later steps in catalyst preparation. Methodsof preparation include solid state ion exchange which is achieved bythermal means, spray drying with a metal salt solution, and preparationof a slurry in a salt solution. The slurry may be filtered to retrievethe SSZ-32X, now loaded with metal.

Inactive materials can suitably serve as diliuents to control the amountof conversion in a given process so that products can be obtainedeconomicailly without using other means for controlling the rate ofreaction. Frequently, zeolite materials have :been incorporated intonaturally occurring clays, e.g., bentonite and kaoliin. These materialse.g. clays, oxidees, etc., function, in part, as binders for thecatalyst. It is desirable to provide a catalyst having good crushstrength, because in petroleum refining the catalyst is often subjectedto rough handling. This tends to break the catalyst down into powderswhich cause problems in processing.

Naturally occurring clays which can be composited with the syntheticSSZ-32X of this invention include the montniorillonite and kaolinfamilies, which families include the sub-bentonites and the kaolinscommonly known as Dixie, McNamee, Georgia and Florida clays or others inwhich the main mineral constituent is halloysite, kaolinrite, dickite,nacrite, or anauxite. Fibrous clays such as sepiolte and attapulgite canalso be used as supports. Such clays can be used in the raw state asoriginally mined or can be initially subjected to calcination, acidtreatment or chemical modification.

The mixture of SSZ-32X and binder can be formed into a wide variety ofphysical shapes. Generally speaking, the mixture can be in the form of apowder, a granule, or a molded product, such as an extrudate having aparticle size sufficient to pass through a 2.5-mesh (Tyler) screen andbe retained on a 48-mesh (Tyler) screen. In cases where the catalyst ismolded insuch as by extrusion with an organic binder, the mixture can beextruded before drying, or dried or partially dried and then extruded.SSZ-32X can also be steamed. Steaming helps stabilize the crystallinelattice, to attack from acids. The dried extrudate is then thermallytreated, using calcination procedures.

Calcination temperature may range from 390 to 1100° F. Calcination mayoccur for periods of time ranging from 0.5 to 5 hours, or more, toproduce a catalytically active product especially useful in hydrocarbonconversion processes.

The extrudate or particle may then be further loaded using a techniquesuch as impregnation, with a Group VIII metal to enhance thehydrogenation function. It may be desirable to compregnate a modifyingmetal and Group VIII metal at once, as disclosed in U.S. Pat. No.4,094,821. The Group VIII metals preferably platinum, palladium or amixture of the two. After loading, the material can be calcined in airor inert gas at temperatures from 500 to 900° F.

Feeds

The instant invention may be used to dewax a variety of feedstocksranging from relatively light distillate fractions such as kerosene andjet fuel up to high boiling stocks such as whole crude petroleum,reduced crudes, vacuum tower residua, cycle oils, synthetic crudes (eg.,shale oils, tars and oil, etc.), gas oils, vacuum gas oils, foots oils,Fischer-Tropsch derived waxes, and other heavy oils. Straight chainn-paraffins either alone or with only slightly branched chain paraffinshaving 16 or more carbon atoms are sometimes referred to herein aswaxes. The feedstock will often be a C10+ feedstock generally boilingabove about 350° F., since lighter oils will usually be free ofsignificant quantities of waxy components. However, the process isparticularly useful with waxy distillate stocks such as middledistillate stocks including gas oils, kerosenes, and jet fuels,lubricating oil stocks, heating oils and other distillate fractionswhose pour point and viscosity need to be maintained within certainspecification limits. Lubricatinrg oil stocks will generally boil above230° C. (450° F.), more usually above 315° C. (600° F.). Hydroprocessedstocks are a convenient source of stocks of this kind and also of otherdistillate fractions since they normally contain significant amounts ofwaxy n-paraffins. The feedstock of the present process will normally bea C10+ feedstock containing paraffins, olefinis naphthenes, aromatic andheterocyclic compounds and with a substantial proportion of highermolecular weight n-paraffins and slightly branched paraffins whichcontribute to the waxy nature of the feedstock. During the processing,the n-paraffins and the slightly branched paraffins undergo somecracking or hydrocracking to form liquid range materials whichcontribute to a low viscosity product. The degree of cracking whichoccurs is, however, limited so that the yield of products having boilingpoints below that of the feedstock is reduced, thereby preserving theeconomic value of the feedstock.

Typical feedstocks include hydrotreated or hydrocracked gas oils,hydrotreated lube oil raffinates, brightstocks, lubricating oil stocks,synthetic oils, foots oils, Fischer-Tropsch synthesis oils, high pourpoint polyolefins, normal alphaolefin waxes, slack waxes, deoiled waxesand microcrystalline waxes.

Conditions

The conditions under which the isomerization/dewaxing process of thepresent invention is carried out generally include a temperature whichfalls within a range from about 392° F. to about 800° F., and a pressurefrom about 15 to about 3000 psig. More peferably the pressure is fromabout 100 to about 2500 psig. The liquid hourly space velocity duringcontacting is generally from about 0.1 to about 20, more preferablyfrom: about 0.1 to about 5. The contacting is preferably carried out inthe presence of hydrogen. The hydrogen to hydrocarbon ratio preferablyfalls within a range from about 2000 to about 10,000 standard cubic feetH₂ per barrel hydrocarbon, more preferably from about 2500 to about 5000standard cubic feet H₂ per barrel hydrocarbon.

The product of the present invention may be further treated as byhydrofinishing. The hydrofinishing can be conventionally carried out inthe presence of a metallic hydrogenation catalyst, for example, platinumon alumina. The hydrofinishing can be carried out at a temperature offrom about 374° F. to about 644° F. and a pressure of from about 400psig to about 3000 psig. Hydrofinishing in this mariner is described in,for example, U.S. Pat. No. 3,852,207 which is incorporated herein byreference.

EXAMPLES

The synthesis of a broadline zeolite (in reference to the x-raydiffraction pattern) SSZ-32X is really synonymous with crystallizing avery small crystal example of the zeolite. The x-ray diffraction patternbroadens as the crystallites are reduced in size. In general, for thesystem of MTT structure zeolites, of which standard SSZ-32 as well asSSZ-32X are examples, as the S_(i)O₂/Al₂O₃ ratio diminishes (greater wt% Al in the zeolite product) the crystallite size also diminishes.

FIG. 1(a) compares the SSZ-32X peak occurrence and relative intensitywith that of standard SSZ-32. Relative intensity is obtained when anintensity value is divided by a reference intensity and multiplied by100%, or 100 × l/lo.

FIGS. 1(b) and (c) superimpose the SSZ-32X plot on the standard SSZ-32plot, clearly showing the match up of major peaks. FIG. 1(c) shows amore detailed portion of FIGS. 1(b). Table 2(a) shows the peak listingand relative intensity of peaks of standard SSZ-32. Table 2(b) magnifiespeak width so that major peaks of SSZ-32X and standard SSZ-32 tray beeasily compared. TABLE 2(A) Peak listing of standard SSZ-32 Relatived-spacing Intensity (%) 2 Theta (Å) (I/Io) × 100 7.9 11.2 19 8.2 10.8 248.9 10.0 11 11.4 7.8 20 14.7 6.05 2 15.9 5.59 5 11.4 5.41 4 18.2 4.88 1219.6 4.52 69 20.1 4.43 11 20.9 4.25 70 21.4 4.15 9 22.8 3.90 100 23.93.73 53 24.0 3.70 58 24.7 3.61 50 25.2 3.53 36 26.0 3.43 42 28.2 3.16 1129.4 3.03 7 31.6 2.83 13

TABLE 2(B) Peaks in as-made SSZ-32X Relative d-spacing Intensity (%) 2Theta (Å) (I/Io × 100) 8.03 11.0 33 8.83 10.0 6 11.30 7.83 20 15.71 5.643 16.34 5.42 3 18.09 4.90 7 19.54 4.54 33 19.67 4.51 20 20.81 4.27 3121.21 4.18 14 22.74 3.91 63 23.91 3.72 100 24.54 3.62 24 25.09 3.55 3425.87 3.44 31 26.91 3.31 5 28.10 3.17 4 29.34 3.04 5 31.46 2.84 8 31.942.80 3 34.02 2.63 1 35.22 2.55 17 36.29 2.47 16

Example 1 Synthesis of SSZ-32X

A preparation of the desired material was synthesized as follows: AHastelloy C liner for a 5 gallon autoeclave unit was used for the mixingof reagents and then in the subsequent thermal treatment. At a rate of1500 RPM and for a period of ½ hour, the following components were mixedonce they had been added in the order of description. 300 grams of a 1Molar solution of N N′ Diusopropyl imidazolium hydroxide was mixed into4500 grams of water. The salt iodide was prepared as in U.S. Pat. No.4,483,835, Example 8, and then subsequently was ion-exchanged to thehydroxide form using BioRad AG1-X8 exchange resin. 2400 grams of 1 N KOHwere added. 1524 grams of Ludox AS-30O (30 wt % S_(i)O₂) were added.1080 grams of Nalco's 1056 colloid sol (26 wt % S_(i)O₂ and 4 wt %Al₂O₃) were added. Last, 181 grams of isobutylamine were stirred intothe mixture. In general, the molar concentration of the amine Q_(b) mustexceed the molar concentration of the imidazolium compound, Q_(a).

Once the stirring was finished the autoclave head was closed up and thereaction was taken up to 170° C. with an 8 hour ramp up time. The systemwas stirred at 150 RPM. The reaction was terminated so that a productwas collected after 106 hours of heating. The solids were collected byfiltration (which goes very slowly; an indication of- small crystals).It was subsequently washed several times and then dried. The materialwas analyzed by x-ray diffraction and the pattern is shown in Table 3. Acomparison is made with the more standard SSZ-32 data presented in Table2(a) and it can be seen that the new product of Example 1 is essentiallyrelated to SSZ-32 but has the diffraction lines considerably broadened.TABLE 3 Relative d-spacing Intensity (%) 2Θ (Å) Intensity (I/Io × 100)8.00 11.05 15 26 8.80 10.05 6 10 11.30 7.83 10 17 14.50 6.11 1 2 15.755.63 3 5 16.50 5.37 3 5 18.10 4.901 7 12 19.53 4.545 41 71 20.05 4.428 6shoulder 10 shoulder 20.77 4.277 41 71 21.30 4.171 7 12 22.71 3.915 58100 23.88 3.726 57 98 24.57 3.623 30 52 25.08 3.551 25 43 25.88 3.443 2747 26.88 3.317 5 9 28.11 3.174 6 10

In a concern that the product might be a mix of small crystals andconsiderable amorphous material, a TEM (Transmission ElectronMicroscopy) analysis was carried out. The microscopy work demonstratedthat the product of Example 1 was quite uniformly small crystals ofSSZ-32 (the product was SSZ-32X) with very little evidence of amorphouismaterial. The cystallites were characterized by a spread of small, broadlathe-like components in the range of 200-400 Angstroms, The SiO₂/Al₂O₃ratio of this product was 29.

EXAMPLE 2

The product of Example 1 was calcined to 1100° F. in air with a ramp of1 deg. C/min(1.8F/min) and plateaus of 250 F. for 3 hours, 1000° F. for3 hours and then 1100° F. for 3 hours. The calcined material retainedits x-ray crystallinity. The calcined zeolite was subjected to 2ion-exchanges at 200° F. (using NH₄ NO₃) as has been previouslydescribed in U.S. Pat. No. 5,252,527. The ion-exchanged matertal wasrecalcined and then the microporosity measurements were explored, usinga test procedure also described in U.S Pat. No. 5,252,527. The newproduct, SSZ-32X, had some unexpected differences vs. conventionalSSZ-32.

The Ar adsorption ratio for SSZ-32X (Ar adsorption at 87 K between therelative pressures of 0.001 and 0.1)/(total Ar adsorption up to relativepressure of 0.1) is larger than 0.5 and preferably in the range of 0.55to 0.70. In contrast for the conventional SSZ-32, the Ar adsorptionratio is less than 0.5, typically between 0.35 and 0,45. The SSZ--32X ofExamples 1 and 2 demonstrates an Argon absorption fraction of 0.62. Theexternal surface area of the crystallites jumped from about 50 m²/g(SSZ-32) to 150 (SSZ-32X) indicating the considerable external surfaceas a result of very small crystals.

At the same time, the micropore volume for SSZ-32X had dropped to about0.035 cc/gm, as compared with about 0.06 cc/gm for standard SS7-32.

EXAMPLE3

The ion-exchanged SSZ-32X was tested for cracking activity via the useof the Constraint Index test. This test was an important parameter inshowing the unique selectivity of zeolite SSZ-32X. The test is describedin U.S. Pat. No. 5252527, Example 9. Using the test conditions, standardSSZ-32 typically provides a Constraint Index of 13-22 at 50% conversionand 800° F. The product of Example 2 of the instant application, whenrun under the same procedures yields a much lower conversion of about12% while maintaining shape-selective behavior. TABLE 4 CharacteristicsComparison between standard SSZ-32 and SSZ-32X Standard SSZ-32 SSZ-32XDiisopropylimidazolium/silica 0.00 0.05 Product Silica/alumina ratio 35   28-30 Product Ar adsorption fraction* (0.35-0.45)    (0.55-0.70)Constraint index conversion Test 50% 12% Crystal size, microns 0.17   0.01-0.04*Ar adsorption at 87k between the relative pressures of 0.001 and0.1)/(total Ar adsorption up to the relative pressure of 0.1)

EXAMPLE 4

The next surprise concerning this material came from the testing ofisomerization capability using n-hexadecane as feed and Pd metal on theproduct from Example 2 of the instant invention. Pd ion-exchange wascarried out as was previously described in U.S. Pat. No. 5,282,958,Example 1. The catalyst was tested using the procedure described in U.S.Pat. No. 5,282,958, Example 1. Both the new catalyst and a standardSSZ-32 powder at comparable SiO₂/Al₂O₃ gave about 96% conversion ofn-C₁₆at 545° F. The difference is that the new material of Example 2 ofthe instant invention gave an isomerization selectivity of 75.8% vs. avalue of 64% for standard SSZ-32, as disclosed in U.S. Pat. No.5,282,958 Example 1. So even though the zeolite was shown to haveconsiderably less cracking activity in Example 3, the activity forhydroconversion equals that of the standard SSZ-32 and the selectivityis considerably better. One of the main distinctions between thecatalysts was that the standard SSZ-32 produces about 13% material whichis C₆ and lower, and the new zeolite reduces that number to 7%. Liquidyield is increased and light end :production is reduced.

EXAMPLE 5

The catalyst of Example 4 was made, in this instance with Pt rather thanPd. Calcination of the Pt catalyst was at 550° F. for 3 hours. 8 cc ofcatalyst chips (24-42 mesh size) were measured out and packed into astainless steel reactor after drying overnight in air at 500° F. Thecatalyst was then reduced at 500° F. in flowing H₂ at 2300 psig for 1hour. After reduction of the metal, the catalyst was used to isomerize awaxy light neutral hydrocracked feed, API 38.9, having a 33% waxconstraint, and a pour point of 38° C. The whole liquid product from thereactor was split in a stripper into two fractions. The bottoms producttarget was a −15° C. pour point. A standard SSZ-32 catalyst was alsoprepared and treated in an analogous manner. The data in Table 5 belowshows the improvement which is guard upon using the new SSZ-32X as anisomerization catalyst. Once again a main advantage seems to be reducedlight gas production, which may be related to the lower overallintrinsic acidity of this new material. TABLE 5 Product Wt % VI AtC1-C4, C5- 250- Zeolite 700+ 4.1 CSt wt % 250° F. 550° F. Std SSZ-3270.2 127 5.2 9.3 10 SSZ-32X 75.4 129 2.4 6 8.3

EXAMPLE 6

A bound catalyst was made using the SSZ-32X zeolite powder, usingalumina binder, extrusion, base drying and calcination, incipientwetness Pt impregnation and final drying and calcining of the extrudate.The overall Pt loading was 0.32 wt. %. After following loading andactivation procedures similar to the last example, a titration step wasperformed by adding 200 micromroles nitrogen (as tributyl amine) per gmcatalyst. This catalyst was then tested on a waxy 150N hydrocrackatefeed containing 10% wax and a pour point of +32° C. Process conditionsused were a LHSV of 1.0 hr −1,4000 scf/bbl gas to oil ratio and a totalpressure of 2300 psig. In FIGS. 2(a) and 2(b) the observed yield and VIobtained when a bottoms product (650° F. +cut) is contacted with acatalyst comprising SSZ-032X are compared to results obtained when thefeed is contacted with a similar bound catalyst made from standardSSZ-32 zeolite. An improved yield and VI over the range of −5 to 25° C.product pour point is shown.

1-4. (canceled)
 5. A method of preparing a dewaxing catalyst suitablefor use in a process for dewaxing a hydrocarbon feed to produce anisomerized product said catalyst possessing less defined crystallinity,reduced micropore volume, increased surface area and reduced crackingactivity over other intermediate pore size molecular sieves used forisomerization, the feed including straight chain and slightly branchedchain paraffins having 10 or more carbon atoms, the method ofpreparation comprising the following steps: (a) synthesizing a zeolitehaving a mole ratio of silicon oxide to aluminum oxide greater thangreater than about 20:1 to less than 40:1, with crystallites havingsmall broad lathe-like components in the range of 200-400A, and havingthe x-ray diffraction lines of Table 1 by employing the following steps:(i) combining the following reagents in the amounts specified to form amixture: (1) 5 parts of an N-lower alkyl -N-methyl-N′-isopropyl-imiidazolium cation which has been ion-exchanged to thehydroxide form; (2) 20 parts of an alkali metal hydroxide; (3;) 100parts of SiO2 to 3.5 parts of Al203; (4) 20 parts of an alkyl amine.(ii) stirring the mixture of step (i) in an autoclave, under autogenouspressure, in a range of from 500 to 1500 rpm for a period of from 0 to 5hours, (iii) maintaining the mixture at an elevated temperature for aperiod of from 40 to 120 hours to form the crystals of the zeolite;collecting the crystals of the zeolite by filtration or centrifugation;subjecting the crystals to calcifications and ion-exchange, (b) mixingthe zeolite synthesized in stage (a) with a refractory inorganic oxidecarrier precursor and an aqueous solution to form a mixture, the mixturehaving a molecular sieve content from about 10 to about 90 wt %; (c)extruding or forming the mixture from step (b) to form an extrudate orformed particle; (d) drying the extrudate or formed particle of step(c); (e) calcining the dried extrudate or formed particle of step (d);(f) loading of the extrudate or formed particle of step(d) with ahydrogenation component or other modifying metal or metals to prepare acatalyst precursor; (g) drying the catalyst precursor of step (f); (h)calcining the dried catalyst precursor of step (f) to form a finishedbound dewaxing catalyst. 6-7. (canceled)
 8. The method claim 5 (f) whereother modifying metals are selected from the groups consisting ofmagnesium, lanthanum, and other rare earth metals, barium, sodium,praseodymium, strontium potassium, neosdymium and calcium. 9-37.(canceled)